Why is environmental air used as a coolant in the primary heat exchanger?

The use of environmental air as a coolant in the primary heat exchanger is primarily advantageous because it lowers energy consumption. This is due to the fact that utilizing ambient air as a heat exchange medium requires less energy than other methods. By drawing in air from the environment, the system can effectively transfer heat without relying heavily on mechanical refrigeration systems that typically consume significant power. This efficiency not only conserves energy but also enhances the overall efficacy of the cooling process within the system.

The other choices do not accurately capture the primary reason for using environmental air in the heat exchange process. For instance, maintaining system pressure is more related to the design and operational integrity of the entire system and does not directly correlate with the use of environmental air. Similarly, while the removal of humidity is an important function of some cooling systems, it is not the primary reason for utilizing environmental air specifically in the primary heat exchanger context. Lastly, increasing cabin temperature is contrary to the cooling purpose of the heat exchanger; therefore, it does not contribute positively to the rationale for using environmental air.